tgFX is available to control TinyG. The most recent version seems to have problems actually sending Gcode and/or configuring the motors. It is actively being worked on. You can find it at https://github.com/synthetos/tgFX

There is a fork of Universal Gcode Sender by John Lauer that supports TinyG's JSON formatting for sending Gcode. This has been shown to work quite reliably for sending large amounts of Gcode to your TinyG. It is available at https://github.com/johnlauer/Universal-G-Code-Sender